Electrodes utilizing metal compound particles are applied to electricity storage devices, such as a lithium ion secondary battery that has a positive electrode and a negative electrode both formed of metal compound particles, and a lithium ion capacitor that has a positive electrode formed of an active charcoal and a negative electrode formed of a material (e.g., graphene or metal compound) that is capable of reversibly absorbing and desorbing lithium ions. These electricity storage devices are applied as power supplies for information devices, such as a mobile phone and a laptop computer, and for in-vehicle regenerative energy purpose. In the in-vehicle application, in particular, high rate characteristics are required.
In order to achieve the high rate characteristics of an electricity storage device, a lithium ion secondary battery positive electrode activation substance (see Patent Document 1), which a surface of a particular lithium containing composite oxide is covered with one type of carbon material selected from carbon nanotube, graphene, and carbon black that has an average dispersion particle diameter of equal to or smaller than 0.2 μm, is known, but this does not yet achieve sufficient charging and discharging characteristics at a high rate.